U.S. Pat. No. 5,945,163 discloses an apparatus and method for depositing a material on a substrate. In that patent a distributor is utilized which includes a heated permeable member through which a carrier gas and a material are passed to provide a vapor that is deposited on a conveyed substrate. The permeable member is tubular and has an electrical voltage applied along its length to provide the heating and the carrier gas and the material as a powder are introduced into the tubular permeable member for flow outwardly therefrom as the vapor. A shroud extends around the tubular permeable member and has an opening through which the vapor flows for the deposition.
It would be desirable if improved techniques could be provided for producing thin film.
An object of this invention is to provide improved methods for producing thin film.
In accordance with this invention the material to be produced as a thin film is heated to a sufficient temperature T in a furnace placed inside of a vacuum system. An inert carrier gas is flown over/through the heated material and the vapors of the material are entrained in the carrier gas. Carrier gas containing the vapors of the material is directed onto a substrate heated to a temperature below that of the furnace temperature and placed in close proximity to the exit of the furnace.
Carrier gas flow is adjusted to give:
A sufficient degree of entrainment of the material during contact with the source,
A pressure inside the vacuum enclosure that would be high enough to suppress any re-evaporation from the substrate,
The desired deposition rate.
The vacuum system could be pressurized by a secondary inert gas inlet not going through the source to give more flexibility for the adjustment of the carrier gas flow going through the furnace.